Archaeologists working at the Phung Nguyen culture site in the Red River Delta have discovered a cache of turtle carapaces meticulously inscribed with hematite pigments. These artifacts, dating back nearly 4,000 years, appear to have been used in nocturnal riverine festivals where participants would use the reflective properties of the polished shells to 'capture' the light of specific constellations in the water.
Analysis of the inscriptions reveals celestial patterns that correspond to the vernal equinox, suggesting a sophisticated understanding of astronomy linked to agricultural cycles. The research team notes that the hematite was sourced from over 200 kilometers away, highlighting the high value placed on these ritual objects during seasonal gatherings that likely served to unify early tribal communities.